Big Mac’s tapetum lucidum!! The tapetum lucidum is a layer of reflective tissue located behind the retina in the eyes of many nocturnal animals. It acts as a retroreflector, reflecting visible light that passes through the retina back into the eye. This reflection increases the amount of light available to the photoreceptors (rods and cones) in the retina, enhancing an animal’s night vision. Because Big Mac has eye damage from getting hit by a car, we’re able to get a rare up close look at his t